Electroplating bath



Patented Apr. 8, 1930 UNITED ST S PATENT o cE JOSEPH BEDO, OF CLEVELAND, OHIO, ASSIGNOR TO PERMACHROME CORPORA- TION, OF CLEVELAND, OHIO, A CORPORATION OF OHIO nnncraornarme BATE No Drawing.

bath or solution for use in connection with' the electroplating of chromium upon other metals, the object of the invention being to provide such a bath or solution which is characterizedby a quick throw and a more even deposition of the metal carried therein, name- 23 ly, chromium.

The invention further provides a solution or bath which when used in connection with the process disclosed in a copending application filed jointly by Clyde S. Morgan and myself, Serial No. 285,500, filed June 14, 1928, covering a process of plating aluminum,

ess for depositing chromium upon aluminum, an achievement which has long been sought 39 by those skilled in the art.

- My improved plating bath or solution includes, as a novel ingredient, a metallic thiosulphate, particularly a thiosulphate of an alkali metal, such as sodium thiosulphate or potassium thiosulphate. With a metallic thiosulphate such as mentioned above, I employ a compound of the metal to be deposited,

such for example as chromic acid if the metal is to be chromium; The metallic thiosulphate and the compound of the metal to be deposited are' preferably stirred or mixed, after one is added to the other. They maybe com- .bined in different proportions but the preferred proportions are approximately fifty parts of the metallic compound, such as chromic acid and one part of metallic thiosulphate such as the sodium thiosulphate or the potassium thiosulphate.

When these ingredients are mixed I find 59 that a considerable heat is evolved for a time Application filed July 5, 1928. Serial No. 290,689.

and, therefore, believe that the ingredients are chemically combined, but I am not certain of the exact chemical action taking place in such combination.

I have found that by using the above described solution in connection with the proper voltage and amperage of electric current,

such as commonly employed in electrodepostion has particular utility for the deposition of chromium, particularly on aluminum or aluminum alloys, I do not desire to limit myself to the depositionof this metal or to aluminum or aluminum alloys as a base metal, or to the deposition of the plating. metal upon the base metal by any particular process, or to the deposition thereon only after it has been first treated or coated. results in a highly eflicient and practical proc- Having thus described my invention, what I claim is:

1. An electro-plating bath formed by'comsignature.

- JOSEPH BEDO. 

